This application relates to techniques of determining and tuning the core operating voltage on integrated circuits, such as non-volatile memory controllers.
Controller circuits for non-volatile memory devices frequently have a voltage regulator. The voltage level of the regulator is dependent on the process. During wafer sort, each voltage regulator on every die is tested for appropriate voltage levels and the regulators are trimmed to provide the required voltage levels. The trimmed values can then be stored in a one-time programmable memory on the circuit. Next time, when the die is powered up, the values stored in the one-time programmable memory are read and voltage levels of the regulators are boosted up/lowered down to the expected level. The above procedure can also be repeated for other regulators on the ASIC.
Although this technique can be used to tune the controller's operating voltages, it requires a trimming process and the trim values need to be stored in a one-time program, using valuable circuit area. Further, although the trimming may be accurate when set, over time or variations in operating conditions the accuracy may not be so good.